Self-locking shackle seal



June 28, 1960 K, R, MCCLURE SELF-LOCKING SHACKLE SEAL Filed April 18, 1958 United States Paten-t O i' 2,942,908 Y SELF-LOCKING sHAcxLE SEAL Kenneth R. McClure, St. Charles Township, Kane County, Ill., assigner to Wallace J. Dickey, St. Charles Township, Kane County, lll.

Filed Apr. 18, 1958, Ser. No. 729,333

8 Claims. (Cl. 292-324) The present invention relates generally to self-locking shackle seals, better known as car seals, and in particular to an improved construction thereof.

Car seals are'designed with two major objectives. -A foremost objective is to provide a seal which is tamperproof, that is, which cannot be unsealed by tampering and so repaired as to conceal the tampering. Another objective is economy in manufacture. Attempts to meet both objectives have resulted in a wide variety of seals over the course of time. y

One of the effective structures for the self-locking mechanism is the type shown in Mackey No. 2,343,564 in which the insertion of the free end of a shackle strip into a casing wherein the other end is anchored, displaces a pair of opened spring split rings into a position where they close and lock the said inserted end against withdrawal. The locking structure is housed in a-casing Patented June 28, 1960 another opening later described. The projecting strip 15 is the end of the strip 16 which is doubled back on itself within the casing.

Fig. 2 is an enlarged 'view of the casing showing the parts 11 and 12 before the in-turned ange 13 (dotted line) is formed from the band portion 12. Before the flange 13 is crimped in to place, the free end 17 of the shackle strip I16 is threaded through the slot 14 as far as possible, being stopped by an obstruction integral with the shackle strip, which obstruction is located so that the short end 15. may also pass through the slot.

Heretofore, various means have been provided to serve as the said obstruction, and the present invention is an improvement not only providing said obstruction but serving to strengthen the shackle strip internally and also to form a limiting guideway for the open split rings.

Fig. 3 is a 'fragmentary cross-section showing the strip 16 passing through the slot 14,V and the strip 15 also emerging. lInside the casing the two strips 15 and 16 are connected at the reverse fold 20. The two strips have a recess 21 inwardly from the fold line 20 (see Fig. 4); and inwardly from the slot-region of the casing and inwardly beyond the recess there are registering holes 22 the holes 22.

which commonly has a seal or joint subjectto -being opened by unlawful tampering, but practically impossible to repair for concealing the tampering. 'The present invention employs such a self-locking structure ofthe' above-described type, but with improvements.V L

I It is an object of the present invention tofprovide'an improved seal having a structure which isv tamper-proof to the extent that itis incapable of repair.. i 'Y It is a particular object to provide a seal with aV shackle firmly held within the casing against force to Withdraw it. Various other and ancillary objects and advantages of the invention will become apparent from the following description and explanation of the improved seal and the method of manufacture shown in the accompanying ,drawings in which:

Fig. l is a View of the completed seal ready for locking action.

Fig. 2 .-isan enlarged cross-section of the casing parts as positioned before closing the casing.

Fig. 3 is a cross-section similar to Fig. 2 with the locking mechanism in position. l

Fig. 4 isa plan view .of the. locking :mechanism as viewed within the casing, showing the `rings and the casing in cross-section.

Figs. 5 and 6 are the views similar to Figs. 3 and 4 of a modified locking mechanism.

The invention is not to be considered as limited to and by the form illustrated in the drawings.

Fig. 1 shows the finished seal. It has a casing 10, preferably globular as made of two generally hemispherical Y parts 11 and 12 having originally nesting cylindrical bands 11 and 12 at the diametrical openings.

Part 12 has an elongated slot I14 of uniform width from which emerge two at strips 15 and 16 of equal thickness with a space between them but slightly wider than their thickness freely to receive the remote end 17 of the strip 16 which end has a hole 18 therein for conventional use. ln the well-known structure of this nature, the end 17 may be inserted into the slot between the strips 15 and 16 to push back conventional split-ring means to the point where they close into hole 18 When it is coincident with and 22 with the flat of each strip extendingA longitudinally away from opposite lsides of the holes. The at areas 23 and 24 are those'on which the split ends of rings 26 and 27 normally reside and then slide in reaching The material of at least one, and preferably both of the adjacent strip sections, has an upset ridge in a U-form withlegsv` encompassing flat areas 23 or 24 and tangent to holes22 thus to limit the region for lateral play of the rings and to guide them. The legs of the U are designated 3U and 31 as seen in Fig. 4, with the preferred opposite parts '30' and 31' of which only 31' is shown in Fig. 3. The Ul-legs define the lateral edges of the strips containing them, and in upsetting the strip it becomes narl owed as shown. 'I'he legs preferably extend beyond the additional reinforcement between the holes 22 and re-l holes 22 to the' region of the recess 21, thereby giving! greater strength and rigidity to the fiat strip. As shown in Figs. 5 and 6, the legs 33 and 34 with or without legs 33 and 34 may be shorter thereby dispensing with such cess 21.

In Figs. 3 and 4, the U-form has a base 36 with or without a like base 36' formed as an upstanding ridge or obstruction with at least a portion locatedY at the interior` .having said shorter legs 33 and 34 and corresponding U-bases 37fand 37' likewise to res-ist withdrawal force. The peripheral contour of the U-bases 36 and 37 is preferably rounded to conform to the interior curve of the casing thus to distribute any Withdrawal force over the width of the slot and minimize danger of deforming the casing at the slot.

The longer legs of Figs. 2 and 3 are preferred, as well as is the duplication thereof in the two adjacent strips 15 |and 16. Not only may there be force to withdraw the strips but attempts may be made to ram the parts inwardly against the rear wall of casing section 11, at which contact is normally made by the corners 40 and 41. Without said longer legs such ramming may result in bending or twisting of the strips in the region between the lholes 22 and the fold 20.- j

The operation of the seal is not changed by the improved structure. When the free end 17 is inserted into the casing between the adjacent strips therein, its end strikes the rings Vat the region 43 in Fig. 3, forcing the rings outwardly of the recess 21 and moving the split Vthis locking, the obstruction formed by the base of a U resists attemptsto withdraw the locked shackle.

It is to be understood that numerous changes and modications in departure from the illustrated seal, are contemplated as falling within the `scope of the invention as expressed in the appended claims.

' I claim: n

l. A shackle seal comprising a hollow easing having an elongated slot of uniform width opening into the casing, Va metal shackle stp reversely folded. wit-hin Vthe casing and having two portions thereof emerging from the casing through only "a portion of the width of the slot, one of said strip portions providing a shackle and having a freeV end adapted to enter Vthe-casing through the remaining width of the slot, said remaining width being substantially the thickness of said .end freely to receive said end, the reversely folded Aportions of said strip within the casinghaving a recess inwardly from the fold for receiving split-ring means and having inwardly from said recess and inwardly from the region of the slot registeringrholes, resilient split-ring means normally having split ends held apart by and resting on said strip portions between said registering holes yand said slot region when the diametrically opposite portion of the said ring means resides in said recess,.at least one of said strip portions Ywithin the casing having an outwardly upset ridge from the normall plane of the strip in ,the form of a U with the legs of the U tangent .to said holes andthe base of the VU-shaped lin conformity with the contour of the interior wall `of the casingadjacent the slot and located at said wall, said free end of the shackle having a hole inwardly from its terminal edge to register with the holes in the reversely folded portions within the casing for receiving the ring means in locking action.

2. A seal in accordance with claim 1 in which the legs of the upset U extend beyond the registering holes and to the region of the recess in the fold.

t 3. A seal in accorda-nce with claim l Iin which the legst-of the upset U constitute the lateral edges of the Vupset strip portion. t

4. A Vshackle seal `comprising a hollow casing having an elongated slot'of uniform width opening into the casing, a metalk shackle strip. reversely folded within the casing and having two portionsthereof emerging from the casing through only a portionofthe width of the slot, `one of said Ystrip portions providing a` shackle and a Y Vhaving aV free end adapted'V to enter the .casing through Vthe remaining widthof the slot, said remaining width being substantially the thickness of said end freely to receive said end, the reversely folded portions of said strip within the casing having a recess inwardly fromv Y the fold yfor receiving .split-ring, means yand .having in-V contour of the interior wall of the casing adjacent the slot and located at said wall, .said -f-ree end of the shackle having a hole inwardly from its .terminal edge to register with the holes inthe reversely folded portions within the casing for receiving the `ring means in locking action.

5. A seal in accordance with claim 4 in which the legs of the upset Us extend beyond the registering holes and to the region of the recess in the fold.

6. A seal in accordance with claim 4 in which the legs of the upset Us constitute Athe lateral edges of the upset strip portions. V

7. A shackle seal comprising a hollow casing having an elongated slot of uniform kwidth opening into the casing, a metal shackle strip `reversely folded within the casing and having two portions thereof emerging from the casing through only a portion of the width of the slot, one of said strip portions providing a shackle and'having a free end adapted to enter the casing through the remaining width of the slot, said remaining width being substantially the thickness `of 'said end freely to receive said end, the reversely folded portions of said strip within the casing having a recess inwardly Vfrom the Vfold for receiving split-ring means and having 'inwardly from said recess and inwardly from therregion ofthe slot registering holes, resilient split 'ring ,means normally having split ends held apnrtby and resting on said stripportions betweenpsaid registering holes and said slot region when the diametriadjacent the slot, said free end of the strip having a hole inwardly lfrom its terminal edge `to register'with theholes in the reversely folded .portionsV within the casing for receiving the ring means in locking action. Y

8. A seal in accordance withpclaim 7 in which both strip portions within the easing have said form of U.

References Cited in the iile of'this patent UNrrED STATES PATENTS 

